1. Field of the Invention
The present invention relates to a method for automatically properly discriminating maintenance timing for injection molding machines.
2. Description of the Related Art
An injection molding machine includes expendable parts, such as an injection screw, heating cylinder, mold, etc. When the properties of the expendable parts gradually worsen due to wear, corrosion, etc., the mold may be insufficiently loaded with a resin, or the dwell pressure applied to the mold at the time of mold clamping may be lowered, so that normal molding operation is hindered. Conventionally, therefore, the injection molding machine is disassembled, for example, to replace an expendable part or parts whose performance is worsened, in case of defective molding. If maintenance of the various expendable parts is carried out after detecting the defective molding, however, production of a large number of defectives cannot be avoided. Moreover, a considerable number of expendable parts are subject to deterioration in case of defective molding, and besides, the relationships between the type of defective molding and the types of the expendable parts affected by the defective molding are complicated, so that much labor is entailed by, for example, operation for specifying the expendable parts which require a counterplan to be considered.
Generally, in order to avoid such an awkward situation, the injection molding machine is periodically disassembled, and its expendable parts are subjected to maintenance and inspection. Since the degrees of deterioration of the expendable parts vary depending on the molding conditions, however, it is difficult to determine the timing for the maintenance and inspection properly. The disassembling operation may possibly damage the injection molding machine. If the maintenance operation is repeated too often, therefore, the injection molding machine is liable to be damaged, or labor is wasted, so that the operating efficiency of the injection molding machine lowers.